Wash. Rev. Code § 39.34.200
Any two or more public agencies may enter into agreements with one another to form a watershed management partnership for the purpose of implementing any portion or all elements of a watershed management plan, including the coordination and oversight of plan implementation. The plan may be any plan or plan element described in RCW 39.34.190(3). The watershed partnership agreement shall include the provisions required of all interlocal agreements under RCW 39.34.030(3). The agreement shall be filed pursuant to RCW 39.34.040 with the county auditor of each county lying within the geographical watershed area to be addressed by the partnership. The public agencies forming the partnership shall designate a treasurer for the deposit, accounting, and handling of the funds of the partnership. The treasurer shall be either a county treasurer or a city treasurer of a county or city participating in the agreement to form the partnership.
RCW 39.34.200
Finding-Intent-2003 c 327: See note following RCW 39.34.190.